Generally, an internal cavity of a patient may be contracted or blocked due to diseases of the patient, leading to the functional deterioration and the functional disorder of the internal organs of the patient.
Moreover, the contraction or blockage of the internal cavity obstructs foods and biles, or blood from smoothly flowing in the stomach, the gullet, and the liver, or blood vessels of the patient, and may develop a complication.
In such a case, a contracted or blocked target portion of the internal cavity having a lesion must be expanded. At this time, for example, a stent may be effectively used to expand the target portion of the internal cavity with the lesion.
With reference to FIGS. 1 and 2, the conventional stent proposed by the inventor of this invention is fabricated by knitting superelastic shape-memory alloy wires 2 as a way to allow the superelastic shape-memory alloy wires 2 to cross each other at different positions to make a hollow cylindrical stent body 5 having a net structure with a plurality of diamond-shaped meshes 3. At this time, an insertion terminal and a discharge terminal, each having a plurality of curved portions positioned at regular intervals, are formed at both ends of the hollow cylindrical stent body 5. Additionally, the hollow cylindrical stent body 5 may be covered with clothes, vinyl-based materials, or artificial blood vessels.
When it is desired to insert the stent into the contracted portion of the internal cavity, the hollow cylindrical stent body 5 is primarily inserted into the contracted target portion of the internal cavity while being contracted in its diameter. Once the stent is inserted into the target portion of the internal cavity using an insertion tool, the stent elastically expands, due to superelasticity of the shape-memory alloy, to expand the contracted target portion of the internal cavity.
However, the conventional stent is used to only expand the contracted target portion of the internal cavity having the lesion, but not to heal the tissue with the lesion of the internal cavity.
Furthermore, the conventional stent covered with the clothes or the vinyl-based materials is problematic in that the stent may be movable within the slippery internal cavity due to smoothness of the clothes or the vinyl-based materials, and thus, the stent may be easily displaced from the target portion of the internal cavity.